Sinorhizobium meliloti modified for the expression of a reporter gene and reduced growth
Date of creation
2017-02-22 12:51 UTC (firstname.lastname@example.org)
Date of publication
2017-02-22 17:02 UTC (email@example.com)
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Sinorhizobium meliloti modified for the expression of a reporter
gene and reduced growth
The genetically modified sinorhizobia constitutively express the
luciferase gene from Photinus pyralis coding for the
luciferin-4-monooxygenase which catalyses a light-producing
reaction and is therefore used as a reporter gene.
The luciferase expression cassette is integrated into the recA gene
of the genome of S. meliloti which plays a central role in
natural recombination processes, DNA repair and the control of gene
expression after DNA damage. Insertion of the luciferase expression
cassette, disrupts the functionality of the endogenous recA gene
As a result of the genetic modification S. meliloti has a
prolonged generation time and a growth disadvantage.
The term Recipient organism refers to an organism (either already modified or non-modified) that was subjected to genetic modification, whereas Parental organisms refers to those that were involved in cross breeding or cell fusion.
The S. meliloti strain Rm2011 was used for the transformation.
Sinorhizobium meliloti modified for the expression of a reporter gene
Selectable marker genes and reporter genes
The luciferase expression cassette was inserted into the coding
sequence of the recA gene by in vivo recombination, leading to a
non-functional recA gene product.
The construct did not contain its own termination sequence. It was
site-specifically integrated into the S. meliloti recA
Gene. The insertion site is located upstream of the endogenous recA
termination region, therefore, transcription termination would be
controlled by that sequence.
- Changes in physiology and/or production
- Selectable marker genes and reporter genes
Recombinase A gene - Sinorhizobium meliloti - RHIML
Changes in physiology and/or production - Growth rate
The insertion of the luc expression cassette into the coding
sequence of the recA gene leads to a loss of function of the recA
S. meliloti needs a host plant to grow and proliferate
properly. Here, the symbiotic interaction partner alfalfa,
Medicago sativa, is used as a host plant.